1. Field of the Invention
This invention relates in general to air conditioners for use on motor vehicles, and in particular to a type having parallel flat tubes, the tubes having internal webs which are perforated to enhance heat transfer.
2. Description of the Prior Art
Parallel flow condensers are becoming more commonly used with air conditioning systems of motor vehicles. In a parallel flow condenser, two headers are spaced apart from each other, one of the headers having an inlet for vapor, and the other having an outlet for condensate. Flat parallel tubes extend between the headers. One or more baffles or partitions locate in the headers for o directing refrigerant flow through the parallel tubes between the headers. Fins are positioned between the parallel flow tubes to enhance heat transfer as air moves across.
The parallel tubes have webs within them, defining separate flow passages extending along the length of the tube. The webs may be extruded with the walls of the tube. In another technique, the web is inserted into the tube and brazed in place. The flow passages are quite small, and the pressures within the flow passages can be fairly high.
The heat exchange is not uniform across the tube from the front or leading edge to the back or trailing edge. Air moving across the tube strikes the front edge first and is warmed a it proceeds to the trailing edge of each tube. Consequently, more heat exchange can take place in the flow passages near the front edge than near the back edge.